1. Field of the Invention
This invention is directed to wellbore operations with strings of tubulars and, in certain particular aspects, to tubular subs and related systems useful for maintaining continuous circulation during joint make-up and break-out.
2. Description of Related Art
There are a variety of known continuous circulation systems; for example, and not by way of limitation, the following U.S. Patents and application present exemplary systems and components thereof: U.S. Pat. Nos. 7,350,587; 7,107,875; 6,412,554; 6,315,051; 6,591,916; 3,298,385; 1,491,986; and U.S. application Ser. No. 11/449,662 filed Jun. 9, 2006.
These are a variety of known wellbore, subs, continuous circulation systems, and related components, including, for example, the disclosures of U.S. Pat. Nos. 2,102,555; 2,158,356; 4,310,050; 4,448,267; 4,646,844; 6,253,861; 6,688,394; 6,739,397; 7,028,787; 7,134,489; and 7,281,582; and U.S. Applications Publication Nos. 2002/0157838 published Oct. 31, 2002; and 2006/0254822 published Nov. 16, 2006—all said patents and said applications incorporated fully herein for all purposes.
In the drilling industry, e.g. in the field of drilling for oil, natural gas and other hydrocarbons, drill strings are used that include a large number of tubular sections, referred to as “tubulars”, which are connected by male threads on the pin ends and female threads on the box ends. In many operations such tubulars are added to the drill string, one-by-one, or in “stands” of two or three connected tubulars, as the string carrying a drill bit drills into the ground. Often it is necessary to withdraw the drill string, in whole or in part. Again, each tubular or stand is unscrewed, one-by-one, as the drill string is brought up to the extent required.
With some prior systems, each time that a tubular is added or removed, the drilling process is stopped and the circulation of drilling fluid ceases. Resulting delays in the overall drilling operation are expensive. The circulation of drilling fluids can be extremely critical to maintaining a steady down hole pressure and a steady and near constant equivalent circulating density. Often when tripping a drill string into or out of a well, the lack of continuous circulation of a drilling fluid can cause pressure changes in the well which increase the probability of undesirable “kicks”. The connection of sections of casing in a wellbore present similar problems with circulating fluids.
Various prior systems have a variety of disadvantages and problems associated with their use; for example, in some prior systems valves internal to a sub are sent down a well where they are susceptible to wear and failure. Many items (e.g. fishing tool, logging equipment, downhole tools, etc.) to be located in a wellbore beneath a sub are limited in diameter to a diameter which will pass through the sub. In certain aspects, a valve seat portion of a sub will have a relatively small diameter which limits the size of items which can be inserted through the sub.
“Iron roughnecks,” combine a torque wrench and a spinning wrench to connect and disconnect tubulars, e.g. drilling components, e.g. drill pipe, in running a string of tubulars into or out of a well. Prior art iron roughnecks are shown. e.g., in U.S. Pat. Nos. 4,023,449; 4,348,920; 4,765,401; 6,776,070; 7,062,991; 7,188,547; and 7,313,986, all of which are incorporated herein by reference in their entirety. Certain prior art iron roughnecks have a spinning wrench and a torque wrench mounted together on a carriage. For making or breaking threaded connections between two tubulars, e.g. joints of drill pipe, certain iron roughnecks have a torque wrench with two jaw levels. An upper jaw of the torque wrench is used to clamp onto a portion of an upper tubular, and a lower jaw clamps onto a portion of a lower tubular, e.g. upper and lower threadedly connected pieces of drill pipe. After clamping onto a tubular, the upper and lower jaws are turned relative to each other to break or make a connection between the upper and lower tubulars. A spinning wrench, mounted on the carriage above the torque wrench, engages the upper tubular and spins it until it is disconnected from the lower tubular (or in a connection operation, spins two tubulars together prior to final make-up by the torque wrench).
Certain iron roughnecks are mounted for movement from a wellbore center to a retracted position which does not interfere with or block performance of other operations relative to the well and rotating or driving apparatuses. Such a prior art system can be used for making and breaking joints in a main string or for connecting to or disconnecting from a tubular section located apart from a wellbore center, e.g. in a mousehole (or rathole) at a side of a well.
Certain prior art iron roughneck systems include a carriage for rolling on the surface of the rig floor along a predetermined path. In certain prior art systems a spinner and torque wrench are mounted for upward and downward movement relative to a carriage, for proper engagement with tubulars, and for tilting movement between a position in which their axis extends directly vertically for engagement with a vertical well pipe and a position in which the axis of the spinner and torque wrench is disposed at a slight angle to true vertical to engage and act against a pipe in an inclined mousehole. In certain prior art systems, a spinner is movable vertically with respect to a torque wrench.
There are a variety of known torque wrenches and tongs for use in wellbore operations, e.g., but not limited to, as disclosed in and referred to in U.S. Pat. Nos. 3,892,140; 4,221,269; 4,425,827; 4,446,761; 6,684,737; 6,971,283; 5,161,438; 5,159,860; 5,842,390; 5,245,877; 5,259,275; 5,390,568; 4,346,629; 5,044,232; 5,081,888; 5,167,173; 5,207,128; 5,409,280; 5,868,045; 6,966,385; 6,138,529; 4,082,017; 6,082,224; 6,213,216; 6,330,911; 6,668,684; 6,752,044; 6,318,214; and 6,142,041; 6,253,845; and 7,000,502.